Molecular and functional characterization of allogantigen-specific anergic T cells suitable for cell therapy

Abstract

Background CD4+ regulatory T cells are a specialized subset of T cells that actively control immune responses. Several experimental protocols have been used to expand natural regulatory T cells and to generate adaptive type 1 regulatory T cells for regulatory T-cell-based therapies. Design and MethodsThe ability of exogenous recombinant human interleukin-10 to induce alloantigen-specific anergy in T cells was investigated and compared to that of interleukin-10 derived from tolerogenic dendritic cells, in mixed lymphocyte cultures. A detailed characterization of the effector functions of the resulting anergized T cells is reported. ResultsInterleukin-10, whether exogenous or derived from tolerogenic dendritic cells, induces a population of alloantigen-specific T cells (interleukin-10-anergized T cells) containing type 1 regulatory T cells, which are anergic and actively suppress alloantigen-specific effector T cells present within the mixed population. Interleukin-10-induced anergy is transforming growth factor-β independent, and is associated with a decreased frequency of alloantigen-specific cytotoxic T lymphocyte precursors, but interleukin-10-anergized T cells are still responsive to third-party, bacterial, and viral antigens. Tolerogenic dendritic cells are more powerful than exogenous interleukin-10 in generating type 1 regulatory T-cell precursors, and are also effective in the context of HLA-matched donors. ConclusionsBased on these studies, we have developed an efficient and reproducible in vitro method to generate antigen-specific type 1 regulatory T-cell precursors starting from total peripheral blood cells with minimal cell manipulation and suitable for generating type 1 regulatory T cells for regulatory T-cell-based therapies. therapy. Haematologica 2010;95(12): 2134-2143. doi:10.3324/haematol.2010 This is an open-access paper. © F e r r a t a S t o r t i F o u n d a t i o n Key words: regulatory T cells, immune responses, exogenous recombinant human IL-10. Citation: Bacchetta R, Gregori S, Serafini G, Sartirana C, Schulz U, Zino E, Tomiuk S, Jansen U, Ponzoni M, Paties CT, Fleischhauer K, and Roncarolo MG. Molecular and functional characterization of allogantigen-specific anergic T cells suitable for cell Molecular and functional characterization of allogantigen-specific anergic T cells suitable for cell therapy

HLA-G expression levels influence the tolerogenic activity of human DC-10

“…In addition, our data sustain the key role of IL-10 in DC-10-induced T-cell anergy (and Tr1 cells), 27,[43][44][45] since, in a limited number of donors, T cells primed with HLA-G low DC-10 became hypo-responsive to secondary stimulation. Data presented in this study demonstrated that, although IL-10-derived by DC-10 is necessary to promote T-cell anergy, it is not sufficient to promote the differentiation of Tr1 cells at high frequency.…”

“…[40][41][42][43] We have demonstrated that IL-10, either exogenously added or derived by DC-10, inhibited the proliferation of allogeneic naïve T cells in vitro. 44,45 DC-10 promote Tr1 cell differentiation via the IL-10-induced HLA-G/ILT4 pathway.27 Although IL-10, ILT4, and HLA-G are important for DC-10 tolerogenic activity, their relative contributions in inducing Tr1 cells were not investigated. The identification of DC-10 that spontaneously expressed high or low HLA-G finally allowed us to demonstrate that the high levels of HLA-G on DC-10 are required for efficient induction of anergic T cells, and consequently Tr1 cells.…”

Dendritic Cell Immune Therapy to Break or Induce Tolerance

“…The high expression levels of HLA-G and the high IL-10/IL-12 production ratio render DC-10 potent inducers of allo-specific Tr1 cells [24,83]. The clinical use of DC-10 relies on this latter feature, and clinical-grade protocols for the induction of allo-specific Tr1 cells, suitable for cell therapy, using DC-10 have been developed [84,85]. In addition to this clinical application, we are currently testing the potential use of DC-10 as cell therapy for tolerogenic DCbased approaches [7,11].…”

T Cell Immunotherapy for Immune Reconstitution and GVHD Prevention After Allogeneic Hematopoietic Stem Cell Transplantation

“…In fact, donor T cells primed ex vivo with host APCs and IL-10 are anergic towards host-HLA antigens but contain host-specific Tr1 cells and memory T cells able to respond to pathogens [93]. The five patients treated with this approach showed improved immune reconstitution, and four of them are alive with complete disease remission at 7.2 years (range 6.4-8.3) after HSCT [94,95], thus providing the first proof-of-concept of feasibility and safety of Tr1 cellbased therapy and suggesting a clinical benefit of the use of Tr1 cells after HLA-haploidentical HSCT.…”